> However, researchers (not me) are already looking for ways to extract data from the libraries. I think it's only a matter of time before this becomes a much bigger problem.
What's the use of the data, and what problems do you see?
What's the use of the data, and what problems do you see?
> Perhaps there is a reason that they don't want really technical people looking at PhotoDNA. Microsoft says that the "PhotoDNA hash is not reversible". That's not true. PhotoDNA hashes can be projected into a 26x26 grayscale image that is only a little blurry. 26x26 is larger than most desktop icons; it's enough detail to recognize people and objects. Reversing a PhotoDNA hash is no more complicated than solving a 26x26 Sudoku puzzle; a task well-suited for computers.
> I have a whitepaper about PhotoDNA that I have privately circulated to NCMEC, ICMEC (NCMEC's international counterpart), a few ICACs, a few tech vendors, and Microsoft. The few who provided feedback were very concerned about PhotoDNA's limitations that the paper calls out. I have not made my whitepaper public because it describes how to reverse the algorithm (including pseudocode). If someone were to release code that reverses NCMEC hashes into pictures, then everyone in possession of NCMEC's PhotoDNA hashes would be in possession of child pornography.
https://www.hackerfactor.com/blog/index.php?/archives/929-On...
This doesn’t seem to be true. These are 26×26 icons, for instance:
https://cdn.dribbble.com/users/975594/screenshots/6193663/ic...
torso: https://imgur.com/a/Oz0pnyF
closeup of face: https://imgur.com/a/Hr1OS2P
I guess it has to be decided if wide access to blurry images like this is better or worse than finding full resolution images. This all assumes there's not some obfuscation layer, I suppose (is that possible?).
We don't know how Apple's solution works. But if it can project recognizable images, then it means people can use Apple's hash system to regenerate child porn.
Without details and an actual code review, I'm not willing to accept Apple's assurance that an image projection isn't possible. We hear that same promise from Microsoft's PhotoDNA, and it turned out to be false.
Imagine the problems if every iPhone and every Mac was in possession of child porn because Apple put it there...
Yes, this is a lot of 'if's, but until it has been evaluated, it is in the very real realm of possible.